The prior art devices for intravaginal, barrier-type prevention of conception and sexually transmitted disease include the diaphragm and the cervical cap. The diaphragm, when seated intravaginally, acts as a barrier to prevent sperm from entering the os of the cervix. A spermicide is used on the inside of the diaphragm to kill sperm traversing over the edge of the diaphragm. Characteristically, the diaphragm is a shallow rubber cup with a rim. A round, coiled metal spring is disposed in the rim. The diaphragm is intended for intravaginal disposition between the posterior aspect of the pubic bone and the posterior fornix. When thus seated, the diaphragm presses against the vaginal wall to form a continuous barrier therewith.
The cervical cap is a small, vaulted or domed device, more rigid than the diaphragm, and dimensioned to fit over a cervix, where it is retained by suction, rather than spring tension, as is the diaphragm. The cap includes a dome which rises from a rim. The cap is slipped over the cervical protrusion to block access to the uterus through the cervical os.
None of these barrier-type devices is adapted to fit in close anatomical sealing engagement between the vagina and the cervix. The diaphragm is held against the upper part of the vaginal canal by the tension of the spring in its rim, while the cervical cap typically engages only the tip of the cervix. Both of these devices can be dislodged by sexual arousal, coital activity, or orgasm. As is known, such dislodgement can reduce the effectiveness of the barrier and permit unintended fertilization or unwanted infection, or worse, both.
In failing to take into account the anatomy and physiology of the vagina and the cervix, the prior art barrier-type devices form imperfect barriers against the penetration of sperm and agents of sexually transmitted diseases into the uterus. As is known, fertilization and infection take place within the uterus, therefore, the more sound the barrier to the cervical os, the greater the likelihood of preventing such fertilization or infection. With the emergence of the AIDS (acquired immune deficiency syndrome) epidemic, the risk of life-threatening infection accompanying heterosexual activity is increasing steadily. Therefore, there is a compelling need for intravaginal, barrier-type devices which can substantially decrease the risk of infection by significantly increasing the effectiveness and reliability of the barrier to entry of bodily fluids such as semen, into the cervix.
Another problem with many of the prior art devices, and with diaphragms and cervical caps in general, is the difficulty associated with proper positionment and engagement of the device with the cervix and vaginal walls to ensure the best possible seal. One feature of the device disclosed herein and in related U.S. Pat. No. 4,858,624 is a vaginal brim which has an increasing height from an anterior vaginal location to a posterior vaginal location. In order to significantly enhance the sealing characteristics, the device is to be positioned with the anterior portion of the brim engaged with the anterior vaginal wall and the posterior portion of the brim engaged with the posterior vaginal wall. What is needed then are means to help insert the device and insure its proper orientation with respect to the vaginal walls.